U.S. patent number 5,034,556 [Application Number 07/333,355] was granted by the patent office on 1991-07-23 for reaction products of alpha-aminomethylene phosphonic acids and epoxy compounds and their use in coating compositions.
This patent grant is currently assigned to PPG Industries, Inc.. Invention is credited to Charles F. Kahle, II.
United States Patent |
5,034,556 |
Kahle, II |
July 23, 1991 |
Reaction products of alpha-aminomethylene phosphonic acids and
epoxy compounds and their use in coating compositions
Abstract
The disclosure is directed to a compound which is a reaction
product of at least one phosphonic acid group of an
alpha-aminomethylene phosphonic acid containing at least one group
corresponding to the formula, ##STR1## with an epoxy group of a
compound containing at least one epoxy group. The disclosure is
also directed to waterborne coating compositions, organic
solvent-borne coating compositions, and powder coating compositions
containing the aforesaid reaction product.
Inventors: |
Kahle, II; Charles F. (Allison
Park, PA) |
Assignee: |
PPG Industries, Inc.
(Pittsburgh, PA)
|
Family
ID: |
23302444 |
Appl.
No.: |
07/333,355 |
Filed: |
April 3, 1989 |
Current U.S.
Class: |
558/155; 558/158;
523/451; 558/169 |
Current CPC
Class: |
C09D
5/024 (20130101); C07F 9/3817 (20130101); C08G
59/4071 (20130101); C09D 5/033 (20130101); C09D
163/00 (20130101); C09D 5/38 (20130101); C09D
7/63 (20180101); C08K 5/5313 (20130101); C08K
5/06 (20130101) |
Current International
Class: |
C09D
163/00 (20060101); C09D 5/03 (20060101); C09D
7/12 (20060101); C08G 59/00 (20060101); C09D
5/02 (20060101); C09D 5/38 (20060101); C07F
9/00 (20060101); C07F 9/38 (20060101); C08G
59/40 (20060101); C09D 005/02 (); C09D 005/38 ();
C07F 009/40 () |
Field of
Search: |
;558/158,169,155 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1276822 |
|
Jun 1972 |
|
GB |
|
2138424A |
|
Oct 1984 |
|
GB |
|
Other References
Goncalves et al., Chemical Abstracts, vol. 89, No. 129606 (1978).
.
Helmut Blum and Peter Christophliemk, "Technical
Aminopolymethylenephosphonic Acids as Scale Inhibitors", pp.
108-114, Phosphorus and Sulfur 30 (1987) 619. .
Phosphates Division of Albright & Wilson, Ltd., `Briquest`
Phosphonates as Sequestrants and Surfactants, pp. 1-4, Product
Technical Information. .
Phosphates Division of Albright & Wilson, Ltd., "Briquest
ADPA-60A", Acetodiphosphonic Acid Aqueous Solution, 2 sheets. .
Monsanto Company, "Dequest 2000 and 2006 Phosphonates", Technical
Bulletin No. IC/WT-101, 5 sheets. .
Monsanto Company, "Dequest 2010 Phosphonate", Technical Bulletin
No. IC/SCS-323, 3 sheets. .
Monsanto Company, "Dequest 2041 and 2051 Phosphonates", 7 sheets.
.
Monsanto Company, "Dequest 2060 Organophosphorus Product",
Technical Bulletin No. IC/SCS-322, 3 sheets. .
Albright & Wilson Inc., "Organophosphorus Chemicals", 1 sheet;
"Flame Retardants", 2 sheets; Surfactants, 2 sheets; Functional
Fluid Additives and Precursors, 2 sheets; Sequestrants, Corrosion
and Scale Inhibitors, 1 sheet; Lubricant Additives, 1 sheet;
Inorganic Chemicals, 2 sheets; Proprietary Metal Finishing
Processes, 1 sheet; and Products by Industry, 2 sheets. .
Alfred Bader, "How To Find A Great Herbicide", Aldrichimica Acta,
vol. 21, No. 1, 1988..
|
Primary Examiner: Rivers; Diana
Assistant Examiner: Bernhardt; E.
Attorney, Agent or Firm: Uhl; William J. Breininger; Thomas
M.
Claims
What is claimed is:
1. A compound which is a reaction product of an
alpha-aminomethylene phosphonic acid corresponding to the formula,
##STR6## wherein a=1, 2 or 3, a+b+c=3, and each R, which may be the
same or different, is selected from the group consisting of alkyl,
aryl, alkaryl, and aralkyl with an epoxy compound selected from the
group consisting of polyglycidyl ethers of polyphenols and glycidyl
ethers of aromatic alcohols; the moles of epoxy groups to moles of
replaceable hydrogen from the phosphonic acid groups being within
the range of 1.0:8.0 to 1.0:1.0.
2. The compound of claim 1 which has been neutralized with ammonia
or an amine.
Description
BACKGROUND OF THE INVENTION
This invention is directed to compounds which are reaction products
of alpha-aminomethylene phosphonic acids and epoxy compounds and to
their use in coating compositions.
U.S. Pat. No. 4,621,112 is directed to the use of an organic ester
of orthophosphoric acid, which ester is the reaction product as
specified of a compound containing a -O-PO.sub.3 H.sub.2 group with
a compound containing an epoxide group, to help prevent the
evolution of gas (alternately referred to in the present
application as "gassing") by the reaction of metallic pigment with
the aqueous phase of a waterborne coating composition. While the
use of such organic esters of orthophosphoric acid may help meet
the object of providing an antigassing additive for such waterborne
coating compositions, a number of disadvantages have been found
with respect to such use. For example, it has been found that dry
films produced from waterborne coating compositions which
incorporate such art known compounds tend to be deficient in
humidity resistance. Moreover, their effectiveness as antigassing
agents is not entirely satisfactory.
The present invention is directed to a new class of compounds which
not only reduce or prevent gassing of waterborne coating
compositions containing metallic pigment better than the aforesaid
art known organic esters of orthophosphoric acid, but, among other
advantages, do not disadvantageously hurt humidity resistance of
dry films produced therefrom compared to such art known organic
esters of orthophosphoric acid. Moreover, the present invention is
also directed to the use of this new class of compounds in organic
solvent borne coating compositions containing organic coloring
pigment to improve the color stability of such solvent-borne
coating compositions. Additionally, the present invention is
directed to the use of this new class of compounds in powder
coatings to improve the dispersibility of pigment therein. These
and other objects of the invention will become apparent to the
reader infra.
SUMMARY OF THE INVENTION
The present invention provides for a compound which is a reaction
product of at least one phosphonic acid group of an
alpha-aminomethylene phosphonic acid containing at least one group
corresponding to the formula, ##STR2## with an epoxy group of a
compound containing at least one epoxy group. Typically the
alpha-aminomethylene phosphonic acid corresponds to the formula,
##STR3## wherein a=1, 2 or 3, a+b+c=3, and each R, which may be the
same or different, is selected from the group consisting of alkyl,
aryl, alkaryl, aralkyl and a monovalent residue of a polyether
compound.
The present invention also provides for a waterborne coating
composition comprising a film-forming polymer, a metallic pigment
and an aqueous diluent medium, wherein the tendency of the pigment
to react with the aqueous medium and release gaseous material is
prevented or reduced by the incorporation in the waterborne coating
composition of an effective amount of a compound of the present
invention.
The present invention also provides for an organic solvent-borne
coating composition comprising a film-forming polymer, a metallic
pigment, an organic solvent medium, and a compound of the present
invention, particularly such organic solvent-borne coating
composition additionally comprising an organic coloring
pigment.
Finally, the present invention also provides for a powder coating
composition comprising a film-forming polymer and a pigment,
wherein dispersibility of said pigment in said powder coating
composition is improved by incorporating therein an effective
amount of a compound of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
A compound of the invention is a reaction product of at least one
phosphonic acid group of an alpha-aminomethylene phosphonic acid
containing at least one group corresponding to the formula,
##STR4## with an epoxy group of a compound containing at least one
epoxy group, preferably with an epoxy group of a compound
containing at least one 1,2-epoxy group. It will be understood that
the two dashes to the left of N in the aforesaid formula represent
two valences on N which are, of course, satisfied in the respective
alpha-aminomethylene phosphonic acid. Typically, in preferred
embodiments of the invention, the alpha-aminomethylene phosphonic
acid corresponds to the formula, ##STR5## wherein a=1, 2 or 3,
preferably a=2, a+b+c=3, and each R, which may be the same or
different, is selected from the group consisting of alkyl, aryl
such as phenyl and the like, alkaryl such as tolyl, xylyl or the
like, aralkyl such as benzyl, phenethyl and the like, and a
monovalent residue of a polyether compound. It is to be understood
that alkyl, aryl, alkaryl, and aralkyl groups as used herein are
considered to include such groups containing one or more hetero
atoms such as nitrogen, oxygen or sulfur, particularly wherein the
aromatic portion of such groups contain such hetero atom.
Examples of alpha-aminomethylene phosphonic acids which may be
utilized in the reaction with an epoxy compound to prepare a
compound of the invention include:
(2-hydroxyethyl)aminobis(methylenephosphonic)acid, i.e., HOCH.sub.2
CH.sub.2 N(CH.sub.2 PO.sub.3 H.sub.2).sub.2 ;
iso-propylaminobis(methylenephosphonic)acid, i.e.,
i-propylN(CH.sub.2 PO.sub.3 H.sub.2).sub.2 ;
n-propylaminobis(methylenephosphonic)acid, i.e., n-propylN(CH.sub.2
PO.sub.3 H.sub.2).sub.2 ; n-butylaminobis(methylenephosphonic)acid,
i.e., n-butylN(CH.sub.2 PO.sub.3 H.sub.2).sub.2 ;
n-hexylaminobis(methylenephosphonic)acid, i.e., n-hexylN(CH.sub.2
PO.sub.3 H.sub.2).sub.2 ;
(2-ethylhexyl)aminobis(methylenephosphonic)acid, i.e.,
(2-ethylhexyl)N(CH.sub.2 PO.sub.3 H.sub.2).sub.2 ;
n-octylaminobis(methylenephosphonic)acid, i.e., n-octylN(CH.sub.2
PO.sub.3 H.sub.2).sub.2 ;
iso-nonylaminobis(methylenephosphonic)acid, i.e.,
iso-nonylN(CH.sub.2 PO.sub.3 H.sub.2).sub.2 ;
dodecylaminobis(methylenephosphonic)acid, i.e., dodecylN(CH.sub.2
PO.sub.3 H.sub.2).sub.2 ; diethylamino(methylenephosphonic)acid,
i.e., (CH.sub.3 CH.sub.2).sub.2 NCH.sub.2 PO.sub.3 H.sub.2 ;
dimethylamino(methylenephosphonic)acid, i.e., (CH.sub.3).sub.2
NCH.sub.2 PO.sub.3 H.sub.2 ; nitrilotris(methylenephosphonic)acid,
i.e., N(CH.sub.2 PO.sub.3 H.sub.2).sub.3 ;
ethylenediaminetetrakis(methylenephosphonic)acid, i.e., [CH.sub.2
N(CH.sub.2 PO.sub.3 H.sub.2).sub.2 ].sub.2 ;
diethylenetriaminepentakis(methylenephosphonic)acid, i.e., H.sub.2
O.sub.3 PCH.sub.2 N[CH.sub. 2 CH.sub.2 N(CH.sub.2 PO.sub.3
H.sub.2).sub.2 ].sub.2 ; benzylaminobis(methylenephosphonic)acid;
reaction products of phosphorous acid and formaldehyde with
polyoxyalkylene polyamines and polyoxyalkylene monoamines (e.g.,
such polyamines and monoamines as available under the trademark,
JEFFAMINE.RTM., from Texaco, Inc.); as well as the products
produced by reacting phosphorous acid, cocoamine, and formaldehyde
(e.g., in a molar ratio of 2:1:2 respectively, as illustrated in
Example 1 below for the preparation of
cocoaminebis(methylenephosphonic) acid). Alpha-aminomethylene
phosphonic acids are generally known compounds and can be prepared
utilizing generally known methods. Many alpha-aminomethylene
phosphonic acids are available commercially.
As set forth above, a compound of the invention is a reaction
product of at least one phosphonic acid group of an
alpha-aminomethylene phosphonic acid, preferably corresponding to
the formula above, with an epoxy group of a compound containing at
least one epoxy group, preferably with an epoxy group of a compound
containing at least one 1,2-epoxy group. Hydroxyl groups may also
be present in such epoxy compounds and often are. In general the
epoxide equivalent weight of the epoxy compounds will range from 44
to about 4,000, typically from about 150 to about 500. The epoxy
compounds may be saturated or unsaturated, cyclic or acyclic,
aliphatic, alicyclic, aromatic or heterocyclic. They may contain
substituents such as halogen, hydroxyl and ether groups.
Examples of epoxy compounds which may be utilized include compounds
as simple as ethylene oxide, propylene oxide, butylene oxide,
cyclohexene oxide, and the like.
Examples of epoxy compounds which may be utilized also include: the
epoxy polyethers obtained by reacting an epihalohydrin (such as
epichlorohydrin or epibromohydrin) with a polyphenol in the
presence of an alkali. Suitable polyphenols include:
2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol-A),
1,1-bis(4-hydroxyphenyl)isobutane,
2,2-bis(4-hydroxytertiarybutylphenyl)propane,
4,4-dihydroxybenzophenone, 1,1-bis(4-hydroxyphenyl)ethane,
bis(2-hydroxynaphthyl)methane, 1,5-dihydroxynaphthalene,
1,1-bis(4-hydroxy-3-allylphenyl)ethane, and the hydrogenated
derivatives of such compounds. The polyglycidyl ethers of
polyphenols of various molecular weights may be produced, for
example, by varying the mole ratio of epichlorohydrin to polyphenol
in known manner.
Examples of epoxy compounds which may be utilized also include: the
polyglycidyl ethers of mononuclear polyhydric phenols such as the
polyglycidyl ethers of resorcinol, pyrogallol, hydroquinone, and
pyrocatechol, as well as the monoglycidyl ethers of monohydric
phenols such as phenylglycidyl ether, alpha-naphthylglycidyl ether,
beta-naphthylglycidyl ether, and the corresponding compounds
bearing an alkyl substituent on the aromatic ring.
Examples of epoxy compounds which may be utilized also include: the
glycidyl ethers of aromatic alcohols, such as benzylglycidyl ether
and phenylglycidyl ether.
Examples of epoxy compounds which may be utilized also include: the
polyglycidyl ethers of polyhydric alcohols such as the reaction
products of epichlorohydrin or dichlorohydrin with aliphatic and
cycloaliphatic alcohols such as ethylene glycol, diethylene glycol,
triethylene glycol, dipropylene glycol, tripropylene glycol,
propane diols, butane diols, pentane diols, glycerol,
1,2,6-hexanetriol, pentaerythritol and
2,2-bis(4-hydroxycyclohexyl)propane.
Examples of epoxy compounds which may be utilized also include:
polyglycidyl esters of polycarboxylic acids such as the generally
known polyglycidyl esters of adipic acid, phthalic acid, and the
like. Other epoxy compounds which may be utilized include: the
monoglycidyl esters of monocarboxylic acids, such as glycidyl
benzoate, glycidyl naphthoate as well as the monoglycidyl esters of
substituted benzoic acid and naphthoic acids.
Addition polymerized resins containing epoxy groups may also be
employed. Such materials may be produced by the addition
polymerization of epoxy functional monomers such as glycidyl
acrylate, glycidyl methacrylate and allyl glycidyl ether typically
in combination with ethylenically unsaturated monomers such as
styrene, alpha-methyl styrene, alpha-ethyl styrene, vinyl toluene,
t-butyl styrene, acrylamide, methacrylamide, acrylonitrile,
methacrylonitrile, ethacrylonitrile, ethyl methacrylate, methyl
methacrylate, isopropyl methacrylate, isobutyl methacrylate,
hydroxyethyl acrylate, hydroxyethyl methacrylate, 2-ethylhexyl
acrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, and
the like.
Many additional examples of epoxy compounds are described in the
Handbook of Epoxy Resins, Henry Lee and Kris Neville, 1967, McGraw
Hill Book Company.
The relative proportions in which the alpha-aminomethylene
phosphonic acid and the compound containing at least one epoxy
group may be reacted together to form a compound of the invention
may vary widely. However typically the amount of
alpha-aminomethylene phosphonic acid and epoxy compound are chosen
to provide a ratio of moles of epoxy groups to moles of replaceable
hydrogens from the phosphonic acid group(s) in a range of from
1.0:8.0 to 1.0:1.0, usually from 1.0:4.0 to 1:0:1.0, and preferably
1.0:4.0. It also should be understood that in the case where the
reactants are polyfunctional, the reaction product is likely to be
a statistical mixture of a number of different molecular species.
With respect to the preferred ratio of 1.0:4.0, it has been found
that in some cases at lower levels of epoxy, the antigassing effect
in a waterborne composition containing metallic pigment such as
aluminum flakes and the humidity resistance of dry films from
waterborne coating compositions incorporating the compound
(reaction product) are not quite as good as at the aforesaid
1.0:4.0 ratio; and at higher levels of epoxy, while the humidity
resistance is improved for dry films from the waterborne
composition, the compounds effect as an antigassing agent in the
waterborne composition containing metallic pigment is diminished
somewhat.
The reaction of the alpha-aminomethylene phosphonic acid and the
compound containing at least one epoxy group may be conducted at a
temperature in the range, for example, of from 25 degrees Celsius
(.degree. C.) to about 150.degree. C., typically in a range of from
about 80.degree. C. to about 100.degree. C., and usually in a range
of from about 85.degree. C. to about 95.degree. C. Where desired, a
catalyst for opening an epoxy ring, for example a tertiary amine,
may be employed in the reaction of the alpha-aminomethylene
phosphonic acid and the epoxy compound, but typically such catalyst
is not utilized in preferred embodiments of the invention. In order
to maintain fluidity of the reaction mixture, especially where the
epoxy compound is a relatively high-melting solid, it may be
advantageous to conduct the reaction in an inert, polar diluent or
solvent, such as 1-methoxy-2-propanol, dioxane, tetrahydrofuran and
the like. Where a polar diluent or polar solvent is employed, the
reaction can be conveniently carried out at the reflux temperature
of the diluent or solvent.
It has been found that incorporation of a compound of the invention
in a waterborne coating composition containing metallic pigment
(one preferred embodiment of the invention) reduces or prevents
gassing of the coating composition. It has also been found that a
compound of the invention can be incorporated in such waterborne
coating composition without disadvantageously affecting humidity
resistance of dry films (coatings) produced from such waterborne
composition. Moreover, it has been found that incorporation of a
compound of the invention in a pigmented waterborne coating
composition can provide enhanced resistance to pigment settling. A
waterborne coating composition of the invention comprises a
film-forming polymer, a metallic pigment, an aqueous diluent medium
and a compound of the invention. The tendency of the pigment to
react with the aqueous medium and release gaseous material is
prevented or reduced by the incorporation of an effective amount of
a compound of the invention therein. Typically for this embodiment
of the invention, compounds of the invention prepared from
alpha-aminomethylene phosphonic acids corresponding to the above
formula in which a=2 and 1,2-epoxy group-containing diepoxides have
been employed.
Although for a waterborne coating composition of the invention, the
reaction product of the alpha-aminomethylene phosphonic acid and
the compound containing at least one epoxy group may be employed
directly as an antigassing agent, typically it will be utilized in
a form in which the reaction product has been neutralized with
ammonia or an amine such as N,N-dimethylethanolamine,
triethylamine, or the like, for example where acidity of the
reaction product in aqueous medium may affect stability of other
constituents of the coating composition, in particular the
film-forming polymer. For example, where the film-forming polymer
is an addition polymer containing carboxylic acid groups which
polymer is rendered soluble or dispersible in water by
neutralization of the carboxylic acid groups with ammonia or an
amine, the addition of unneutralized compound of the invention may
tend to cause precipitation (flocculation) of the film-forming
polymer.
Examples of metallic pigments for utilization in a waterborne
coating composition of the invention include any metallic pigments
which are generally known for use in pigmented waterborne coating
compositions. Examples include metallic pigments, particularly
metallic flake pigments, composed of aluminum, copper, zinc and/or
brass as well as those composed of other malleable metals and
alloys such as nickel, tin, silver, chrome, aluminum-copper alloy,
aluminum-zinc alloy, and aluminum-magnesium alloy. Of the aforesaid
examples, aluminum flake pigment is preferred. Moreover, a
waterborne coating composition of the invention may also include,
and typically does include, one or more of a wide variety of other
pigments generally known for use in coating compositions such as
various white and colored pigments. Examples of white and colored
pigments include generally known pigments based on metal oxides;
metal hydroxides; metal sulfides; metal sulfates; metal carbonates;
carbon black; china clay; phthalo blues and green, organo reds, and
other organic dyes.
Various procedures may be used for incorporating a compound of the
invention into a waterborne coating composition of the invention.
One method is to bring the metallic pigment into contact with the
compound of the invention prior to the incorporation of the pigment
into the waterborne coating composition. This may be done by adding
the compound of the invention to the pigment paste (e.g., pigment
as normally supplied commercially), or it may be added at an
earlier stage such as during the actual production of the pigment.
Alternatively, a compound of the invention may be introduced into a
waterborne coating composition of the invention by simply
introducing it as a further ingredient in the formulation of the
waterborne coating composition, for example during the mixing of
film-forming resin, metallic pigment and aqueous medium together
with other conventional and optional constituents such as
crosslinking agents, co-solvents, thickeners and fillers.
Irrespective of the manner in which a compound of the invention is
incorporated into a waterborne coating composition of the
invention, an amount of such compound generally is employed which
is effective in reducing or eliminating gassing of the metallic
pigment in the aqueous medium. Typically an amount of from 0.50
percent to 25.0 percent by weight, usually from 5.0 percent to 15.0
percent by weight, based on the weight of metallic pigment (e.g.,
aluminum flake) utilized in the waterborne composition, is employed
for this purpose.
A waterborne coating composition of the invention may contain, as
the film-forming polymer, any polymer or polymers generally known
for use in waterborne coating compositions. Examples include
polymers solubilized or dispersed in aqueous medium, for example
via neutralization with ammonia or an amine of carboxylic acid
groups which such polymers may contain, some examples of which
include water solubilized or water dispersed, acrylics, urethanes,
polyesters, epoxies, aminoplasts or mixtures thereof. Such
film-forming polymers can be employed optionally in combination
with various ingredients generally known for use in waterborne
coating compositions containing film-forming polymers of these
general classes. Examples of these various ingredients include:
fillers; plasticizers; antioxidants; mildewcides and fungicides;
surfactants; various flow control agents including, for example,
thixotropes and additives for sag resistance and/or pigment
orientation such as precipitated silicas, fumed silicas,
organo-modified silicas, bentone clays, organo-modified bentone
clays, and such additives based on polymer microparticles
(sometimes referred to as microgels) described for example in U.S.
Pat. Nos. 4,025,474; 4,055,607; 4,075,141; 4,115,472; 4,147,688;
4,180,489; 4,242,384; 4,268,547; 4,220,679; and 4,290,932 the
disclosures of which are hereby incorporated by reference.
Incorporation of a compound of the invention in an organic
solvent-borne coating composition comprising a film-forming
polymer, a metallic pigment and an organic solvent and/or organic
diluent medium can reduce gassing of the coating composition which
can occur with the introduction of moisture, for example, from
various pigments which have not been dried thoroughly before
incorporation in the coating composition, or for example from
atmospheric moisture which sometimes can slowly enter a storage
container for the coating composition over time. It has also been
found that incorporation of a compound of the invention in an
organic solvent-borne coating composition additionally comprising
an organic coloring pigment which tends to result in a color drift
of the coating composition over time, can increase the color
stability of such a solvent-borne coating composition. In a
presently preferred embodiment of the invention, a compound of the
invention utilized for this purpose is prepared using a compound
containing one 1,2-epoxy group. Without intending to be bound
thereby, it is believed that incorporation of a compound of the
invention in an organic solvent-borne coating composition
additionally containing organic coloring pigment (e.g., Carbazole
violet as obtained from GAF Corp.) helps prevent agglomeration of
the metallic pigment (e.g., Al flake) and/or agglomeration of the
metallic pigment with other pigments, for example coloring
pigments, in the solvent-borne coating composition.
Examples of metallic pigments for utilization in an organic
solvent-borne coating composition of the invention include any
metallic pigments which are generally known for use in pigmented
organic solvent-borne coating compositions. Examples include
metallic pigments, particularly metallic flake pigments, as set
forth in the preceding description of metallic pigments for
utilization in waterborne coating compositions of the invention. Of
the aforesaid examples, aluminum flake pigment is preferred.
Additionally, an organic solvent-borne coating composition of the
invention may also include, and typically does include, one or more
of a wide variety of other pigments generally known for use in
coating compositions such as various white and colored pigments.
Examples of white and colored pigments include the generally known
pigments set forth previously in the description of white and
colored pigments for utilization in a waterborne coating
composition of the invention. As for a waterborne coating
composition, various procedures may be used for incorporating a
compound of the invention into an organic solvent-borne coating
composition of the invention such as, for example, bringing the
pigment into contact with the compound of the invention prior to
the incorporation of the pigment into the organic solvent-borne
coating composition via addition to the pigment paste, or during
the actual production of the pigment, or by introduction of the
compound of the invention directly as a further ingredient in the
formulation of the organic solvent-borne coating composition, for
example via mixing of film-forming resin, pigment and organic
medium together with other conventional and optional constituents
such as crosslinking agents, co-solvents, thickeners and fillers.
Irrespective of the manner in which a compound of the invention is
incorporated into an organic solvent-borne coating composition of
the invention, an amount of such compound generally is employed
which is effective in reducing or eliminating gassing over time of
an organic solvent-borne coating composition containing metallic
pigment. Typically an amount of from 0.10 percent to 15.0 percent
by weight, usually from 2.0 percent to 8.0 percent by weight, based
on the weight of metallic flake pigment (e.g., aluminum flake)
utilized, is employed for this purpose. Where a coloring pigment
which tends to cause a color drift of the coating composition over
time is employed in the coating composition, an amount of such
compound generally is employed which is effective in stabilizing
the organic solvent-borne coating composition against such color
change. Typically an amount of from 0.10 percent to 15.0 percent by
weight, usually from 2.0 percent to 8.0 percent by weight, based on
the weight of metallic flake pigment (e.g., aluminum flake)
utilized, is employed for this purpose.
An organic solvent-borne coating composition of the invention may
contain, as the film-forming polymer, any polymer or polymers
generally known for use in organic solvent-borne coating
compositions. Examples include, acrylics, urethanes, polyesters,
epoxies, aminoplasts or mixtures thereof. Such film-forming
polymers can be employed optionally in combination with various
ingredients generally known for use in organic solvent-borne
coating compositions containing film forming polymers of these
general classes. Examples of these various ingredients include:
fillers; plasticizers; antioxidants; mildewcides and fungicides;
surfactants; various flow control agents including, for example,
thixotropes and additives for sag resistance and/or pigment
orientation such as precipitated silicas, fumed silicas,
organo-modified silicas, bentone clays, organo-modified bentone
clays, and such additives based on polymer microparticles described
for example in U.S. Pat. Nos. 4,025,474; 4,055,607; 4,075,141;
4,115,472; 4,147,688; 4,180,489; 4,242,384; 4,268,547; 4,220,679;
and 4,290,932 which have been incorporated by reference herein.
Examples of organic solvents and/or diluents which may be employed
in an organic solvent-borne coating composition of the invention
include: alcohols such as lower alkanols containing 1 to 8 carbon
atoms including methanol, ethanol, n-propanol, isopropanol,
butanol, sec-butyl alcohol, tertbutyl alcohol, amyl alcohol, hexyl
alcohol and 2-ethylhexyl alcohol; ethers and ether alcohols such as
ethyleneglycol monoethyl ether, ethyleneglycol monobutyl ether,
ethyleneglycol dibutyl ether, propyleneglycol monomethyl ether,
diethyleneglycol monobutyl ether, diethyleneglycol dibutyl ether,
dipropyleneglycol monomethyl ether, and dipropyleneglycol monobutyl
ether; ketones such as methyl ethyl ketone, methyl isobutyl ketone,
methyl amyl ketone and methyl N-butyl ketone; esters such as butyl
acetate, 2-ethoxyethyl acetate and 2 ethylhexyl acetate; aliphatic
and alicyclic hydrocarbons such as the various petroleum naphthas
and cyclohexane; and aromatic hydrocarbons such as toluene and
xylene. The amount of organic solvent and/or diluent utilized in an
organic solvent-borne coating composition of the invention may vary
widely. However, typically the amount of organic solvent and/or
diluent can range from about 10 percent to about 50 percent,
usually from about 20 percent to about 40 percent, by weight based
on the total weight of organic solvent-borne coating
composition.
It has also been found that compounds of the invention can provide
particular advantages in powder coating compositions comprising a
film-forming polymer and a pigment. For example, it has been found
that dispersibility of pigment in such powder coating compositions
is improved by incorporating therein an effective amount of a
compound of the invention. Such improved pigment dispersion can
provide advantages such as improved uniformity of color, improved
hiding, improved gloss, improved definition of image (DOI), and
improved flow and leveling of the powder coating composition upon
heating.
The following examples illustrate the invention and should not be
construed as a limitation on the scope thereof. Unless specifically
indicated otherwise, all percentages and amounts are understood to
be by weight. Wherever used herein "pbw" means parts by weight.
EXAMPLE 1
This example illustrates the preparation of cocoamine
bis(methylenephosphonic)acid and its reaction with the diglycidyl
ether of bisphenol-A to prepare a compound of the invention.
A solution containing 98.0 grams (g) of phosphorous acid (1.19
mole) and 75.0 g of 1-methoxy-2-propanol is heated to 85.degree. C.
under a nitrogen atmosphere. Next, 130.0 g of cocoamine (0.66 mole,
available as ARMEEN CD.RTM. and having an amine equivalent weight
of 196) and 98.0 g of a 37 percent by weight solution of
formaldehyde in water (1.20 mole formaldehyde) are added
simultaneously as separate feeds over 1.5 hours to this solution.
The resulting reaction mixture is held for 4 hours at reflux
temperature (98.degree.-100.degree. C.), whereupon a mixture
containing 116.2 g of bisphenol-A diglycidyl ether (0.30 mole,
available as EPON.RTM. 828 from Shell Chemical Co.) and 30.0 g of
1-methoxy-2-propanol is added over 1 hour, after which the reaction
mixture is held at reflux for 1.5 hours. The resulting product is
cooled to 60.degree. C. and then neutralized by the addition of
55.0 g of N,N-dimethylethanolamine (0.62 mole) over 15 minutes
after which the resulting product is allowed to cool to room
temperature. The resulting product, which contains a compound of
the invention, has a Gardner-Holdt bubble tube viscosity of X, a
total solids content of 67 percent by weight, and a pH of 5.35.
EXAMPLE 2
This example illustrates the preparation of cocoamine
bis(methylenephosphonic)acid and its reaction with phenyl glycidyl
ether to prepare a compound of the invention.
A solution containing 864.6 g of phosphorous acid (10.54 mole) and
1440.2 g of 1-methoxy-2-propanol is heated to 85.degree. C. under a
nitrogen atmosphere. Next, 1036.0 g of cocoamine (ARMEEN CD.RTM.,
5.28 mole) and 840.0 g of a 37 percent by weight solution of
formaldehyde in water (10.35 mole formaldehyde) are added
simultaneously as separate feeds over 1.5 hours to this solution.
The resulting reaction mixture is held for 4 hours at 100.degree.
C. (reflux temperature), thereafter cooled to 85.degree. C. after
which 790.0 g of phenyl glycidyl ether (5.26 mole) is gradually
added over 1 hour. The resulting reaction mixture is held at
85.degree. C. for 3 hours, thereafter cooled to less than
60.degree. C., and then neutralized by the addition of 467.0 g of
N,N-dimethylethanolamine (0.5.24 mole) over 30 minutes. The
resulting product, which contains a compound of the invention, is
vacuum stripped to produce a product having a Gardner-Holdt bubble
tube viscosity of Z-4/Z-5, a total solids content of 83.9 percent
by weight, and a pH of 5.05.
EXAMPLE 3
This example illustrates the preparation of cocoamine
bis(methylenephosphonic)acid and its reaction with the diglycidyl
ether of bisphenol-A to prepare a compound of the invention.
A solution containing 135.0 g of phosphorous acid (1.65 mole) and
225.0 g of 1-methoxy-2-propanol is heated to 85.degree. C. under a
nitrogen atmosphere. Next, 161.9 g of cocoamine (ARMEEN CD.RTM.,
0.83 mole) and 131.3 g of a 37 percent by weight solution of
formaldehyde in water (1.62 mole formaldehyde) are added
simultaneously as separate feeds over 1.5 hours to this solution.
The resulting reaction mixture is held for 5 hours at 100.degree.
C., thereafter cooled to 60.degree. C., and then neutralized with a
solution of 73.3 g of N,N-dimethylethanolamine (0.82 mole) in 50.0
g of 1-methoxy-2-propanol. A mixture containing 155.5 g of
bisphenol-A diglycidyl ether (EPON 828.RTM., 0.41 mole) and 50.0 g
of 1-methoxy-2-propanol is added, and the resulting reaction
mixture is heated to 100.degree. C., held at this temperature for 5
hours, and thereafter cooled to room temperature. The resulting
product, which contains a compound of the invention, is a
homogeneous liquid with a Gardner-Holdt bubble tube viscosity of 0
and has a total solids content of 56.7 percent by weight.
EXAMPLE 4
This example illustrates the preparation of cocoamine
bis(methylenephosphonic)acid and its reaction with phenyl glycidyl
ether to prepare a compound of the invention.
A solution containing 135.0 g of phosphorous acid (1.65 mole) and
225.0 g of 1-methoxy-2-propanol is heated to 85.degree. C. under a
nitrogen atmosphere. Next, 161.9 g of cocoamine (ARMEEN CD.RTM.,
0.83 mole) and 131.3 g of a 37 percent by weight solution of
formaldehyde in water (1.62 mole formaldehyde) are added
simultaneously as separate feeds over 1.5 hours to this solution.
The resulting reaction mixture is held for 5 hours at 100.degree.
C., thereafter cooled to 60.degree. C., and then neutralized with
73.3 g of N,N-dimethylethanolamine (0.82 mole). Next, 123.5 g of
phenyl glycidyl ether (0.82 mole) is added; the resulting reaction
mixture is heated to 100.degree. C. and held at this temperature
for 5 hours; and thereafter cooled. The resulting product, which
contains a compound of the invention, is vacuum stripped to remove
solvent and water to produce a product having a Gardner-Holdt
bubble tube viscosity of Z-5 and a total solids content of 82.2
percent by weight.
EXAMPLE 5
In this example a method known as the "Borax Test" disclosed in
U.S. Pat. No. 4,693,754 is used to evaluate the effectiveness of
antigassing agents for the protection of aluminum flake pigment in
a waterborne composition from reaction with water. The "Borax Test"
provides an accelerated testing method whereby aluminum flake
pigment paste is incorporated in a water solution which is 0.024
Molar in Na.sub.2 B.sub.4 O.sub.7 and 0.002 Molar in NaOH (NaOH is
added to adjust the pH to 9.26). The solution is heated in a
constant temperature bath at 140.degree. F. (60.degree. C.) and the
rate of hydrogen gas evolved is recorded. An antigassing agent of
the invention is added to the waterborne composition containing the
aluminum flake (Composition A below) and its relative effectiveness
is evaluated by comparing the rate of hydrogen evolution to that
from comparative compositions which are the same except for the
substitution in one comparative composition of a known antigassing
agent (an organic ester of orthophosphoric acid) prepared
substantially according to Example 1 of U.S. Pat. No. 4,621,112
(Composition B below) and the use in the other comparative
composition of no antigassing agent (Composition C below). (The
aforesaid known antigassing agent is prepared according to Example
1 of U.S. Pat. No. 4,621,112 except for the substitution of
diisopropanol amine for triethylamine as neutralizing agent and
substitution of 1-methoxy-2-propanol for tetrahydrofuran as solvent
in the synthesis.)
The components of the aforesaid compositions A, B and C are as set
forth in the following Table 1.
TABLE 1 ______________________________________ Antigassing
1-Methoxy-2- Borate Composition Al Paste.sup.1 Agent propanol
Solution.sup.2 ______________________________________ A 15.38 g
1.67 g.sup.3 20 ml (milliliters) 25 ml B 15.38 g 2.38 g.sup.4 20 ml
25 ml C 15.38 g None 20 ml 25 ml
______________________________________ .sup.1 A 65.0 percent by
weight solids aluminum flake pigment paste in mineral spirits and
oleic acid (available as 7575 FG Aluminum Paste from Silberline
Manufacturing Co.). .sup.2 A solution containing 0.024 moles/liter
of Na.sub.2 B.sub.4 O.sub. and 0.002 moles/liter of NaOH in
deionized water. .sup.3 The resulting product of example 3 above
(containing compound of the invention) reduced to 30 percent by
weight solids in 1methoxy-2-propanol and water. .sup.4 The known
antigassing agent prepared substantially according to Example 1 of
U.S. Pat. No. 4,621,112 at 21 percent by weight solids in
1methoxy-2-propanol and water.
Compositions A, B and C are placed separately in flasks; each flask
is sealed with a rubber stopper, and immediately placed in a
constant temperature bath heated to 140.degree. F. (60.degree. C.).
The hydrogen gas which is evolved is allowed to escape through a
hole in the stopper into an inverted buret filled with water. The
volume of gas given off, as shown by displacement of water in the
buret, is then recorded at intervals over 24 hours with allowance
made for expansion due to heating the flask and solution. The
results at 5 hours and 24 hours are as summarized in the following
Table 2. The values for milliliters of hydrogen gas evolved set
forth in Table 2 are average values for three separate experimental
runs for each composition. This is done to verify reproducibility.
In Table 2, the symbol ">" means "greater than".
TABLE 2 ______________________________________ Milliliters (ml) of
Hydrogen Gas Evolved Composition 5 Hours 24 Hours
______________________________________ A 0 1 B 17.7 >50 C 34.2
>50 ______________________________________
As can be seen from the results summarized in Table 2 above, the
metallic pigmented, waterborne composition A, containing a compound
of the invention as antigassing agent, exhibits substantially less
gassing than either composition B (containing the organic ester of
orthophosphoric acid as antigassing agent prepared substantially
according to Example 1 of U.S. Pat. No. 4,621,112) or composition C
(containing no antigassing agent).
EXAMPLE 6
Solution acrylic polymers in organic solvents which also contain
inorganic pigments, organic pigments (especially pigment such as
carbazole violet) and aluminum pigments have long been known to be
prone to color instability and pigment agglomeration. This
condition is aggravated by the addition of water and upon heat
aging. In this example 6, a solvent-borne acrylic lacquer coating
composition (available as DURACRYL.RTM. DBC-3704 from PPG
Industries, Inc.) is used for evaluating the ability a compound of
the invention (the product of Example 4 above) to alleviate the
detrimental interactions associated with coatings containing
certain pigments and aluminum flake as noted above.
The product of Example 4 above (containing compound of the
invention) is incorporated into the solvent-borne acrylic lacquer
coating composition by slurrying the product (at a level of 5
percent by weight based on the weight of aluminum solids) with the
aluminum pigment paste prior to formulation into the DURACRYL.RTM.
DBC-3704 coating composition. Test samples 1 though 4 (as set forth
in the following Table 3) are prepared to which are added 0 percent
or 2 percent water on solution weight and which contain either 0
percent or 5 percent by weight of the product of Example 4 above
based on the weight of aluminum flake solids as summarized in Table
3.
TABLE 3 ______________________________________ DURACRYL .RTM.
DBC-3704 coating composition containing: (Percent by weight Product
of Ex. 4 (Percent by weight water based on Al flake solids) Based
on solution) ______________________________________ Sample 1 0 0
Sample 2 0 2 Sample 3 5 0 Sample 4 5 2
______________________________________
Draw-downs (wet films) are prepared of each sample with a 3 mil
Bird drawdown bar on Leneta paper as control for comparison to aged
samples. The samples are divided in two, and half retained for room
temperature aging while the remainder of each sample is sealed in a
separate can for heat aging at 120.degree. F. (48.9.degree. C.).
Drawdowns of each aged sample are made periodically over a 5 week
period and evaluated relative to the control for color shift and
pigment agglomeration. The results are as summarized in the
following Table 4. Agglomeration is evidenced by the appearance of
small lumps upon visual inspection. As used in the following Table
4, "Sl.Ag." means "Slight Agglomeration", "Sev.Ag." means "Severe
Agglomeration", "+C.S." means that a positive change in color of
the sample has occurred, and "N.C." means no agglomeration and no
color change from the Control.
TABLE 4 ______________________________________ Appearance of Films
(Drawdowns) Prepared From Aged Coating Composition Room Temperature
120 Degrees F. Sample 2 Weeks 5 Weeks 2 Weeks 5 Weeks
______________________________________ 1 Sl.Ag. Sev.Ag. Sl.Ag.
Sev.Ag. 2 Sl.Ag. Sev.Ag. Sl.Ag. Sev.Ag. +C.S. +C.S. 3. N.C. N.C.
N.C. N.C. 4. N.C. N.C. N.C. N.C.
______________________________________
As is evident from the results summarized in Table 4 above, the
color stability and resistance to pigment agglomeration in the
DURACRYL.RTM. DBC-3704 coating composition are greatly improved by
the addition of the product of Example 4 (according to the
invention).
* * * * *